Techniques are being perfected to attain primary outgrowth of epithelial cells from 80% or more of explants prepared from transurethral resection (TUR) specimens of prostatic tissue. Such in vitro models will allow for the testing of chemotherapeutic agents or radiation on an individual basis. In an effort to more accurately characterize the cells in the outgrowth biochemical markers for prostatic acinar cells are being sought. This is being approached by the fractionation of human prostatic fluid. The isolated and purified fractions will be used to produce antibodies which can be applied to fingerprint cells.